The woman arrived in Melbourne from the UK on Dec. 26 and tested positive for COVID-19 the next day. She completed 10 days' quarantine then was allowed to fly into Queensland on Jan. 5.
She took a Jetstar flight that arrived late in the day and while authorities have not yet confirmed the flight number, they have urged anyone who might have been on the flight to come forward for testing.
Genome sequencing later confirmed she had the UK variant, and the Queensland government notified on Friday afternoon, Jeannette Young, the chief health officer, said.
But although she has been found to have the UK variant, Young said the woman is low risk because she is at the tail end of her infectious period.
"However anyone in that area around Maleny or on that flight, if they develop any symptoms, could they please come forward immediately and get tested."
The woman is staying at her parents' house in Maleny and advise anyone in the area to get tested immediately if they develop symptoms.
Brisbane remains on high alert after a cleaner at one of the city's quarantine hotels—Hotel Grand Chancellor—was diagnosed with the highly-infectious UK virus strain.
Authorities fear the woman in her 20s was infected and active in the community from Jan. 2, and are utilising the weekend to track down everyone she came into contact with.
Residents in the council areas of Brisbane, Logan, Ipswich, Moreton Bay, and Redlands must stay at home until 6 p.m. on Monday except for essential work and shopping, exercise, to access healthcare, or look after the vulnerable.
They are also required to were a mask when leaving their house, unless under 12 years old.
Premier Annastacia Palaszczuk told reporters that 178 clinics were open in the Greater Brisbane area for people to get tested.
She also called on the public to treat supermarket staff respectfully amid panic buying.
Queensland Health Minister Yvette D'Ath said: "I know some people are concerned that this may go beyond three days—irrespective, we have never shut our supermarkets."
Young would not confirm whether the lockdown will be lifted on Monday, telling reporters "we have to wait and see."
"Anything is a possibility but I won't say how likely any scenario is," she said. "We've seen that at the moment down in Sydney with some very lengthy periods and then another case pop up. We just have to take each day and get the best information we can.
"The best information is when people are out there getting tested," she said.